Question: If $9a + 5b + 5c = -9$ and $7x + 7y = -8$, what is $-40c - 72a - 70y - 40b - 70x$ ?
$= -72a - 40b - 40c - 70x - 70y$ $= (-8) \cdot (9a + 5b + 5c) + (-10) \cdot (7x + 7y)$ $= (-8) \cdot (-9) + (-10) \cdot (-8)$ $= 72 + 80$ $= 152$